Logo Design

I am a locksmith based near Chatsworth House in Derbyshire, UK.
I would like a logo that incorporates some design into the name i.e. using lock/padlock/shield.
My positioning is professional, quality, afforfable, reliable and fast. The name Chatsworth locally is synomymous with quality and prestige.
I have examples that I like from my competitor attached. I like the way the competitor uses a lock and padlock incorporated into the design and the simple clear font but I dont want to look the same. I also like how they invert the colours so black logo on white for web and white on black for van.
I also added a design I have tried to do myself, I like the shied being defense (like a lock) and the top of the shield having the castle effect linking to Chatswoth House (Stately home,)
I will use the logo on my van, website, marketing materials and shirt so would need a none framed version without phone number and strap line.
I am considering a hint of colour which could be used with black or white/silver depending on where I am using it. I would like to stay away from gold (as main competitor colour), and stay away from red and blues due to local football teams. I have looked at Green or maroon. but not sure if its better to stay neutral.
I would need the logo providing in jpg, png & gif.
Happy to provide any more information needed.